Scientists found 2,700 cubic km usable ground water, three times more water than previously thought, underneath the drought-stricken California's Central Valley.

Residents are excited and surprised with the discovery of the underground water reservoir as California's mega drought is now in its fifth year. There is about 60 percent of the state that was in a severe drought. They hope for rain and El Nino to end. It seems grim yet the new discovery of the underground water reservoir brings expectation for them.

The study was printed in the journal Proceedings of the National Academy of Sciences on the week of June 27. It was led by researchers from Stanford's School of Earth, Energy & Environmental Sciences, according to Science Daily.

Robert Jackson, the co-author of the study said that it's not often that you find a 'water windfall,' but they just did. He added that there's far more fresh water and usable water than they expected.

Meanwhile, Mary Kang, another co-author of the study and a postdoctoral associate at Stanford School of Earth, Energy & Environmental Sciences said that their findings are relevant to a lot of other places where there are shortages of water. These include Australia, China and Texas.

According to Smithsonian, the researchers estimate the reservoir, which holds about 2,700 cubic kilometers of water or about 713 trillion liquid gallons. This is more than the Lake Ontario and Lake Erie when combined. They also examined the data from 938 oils and gas pool and over 35,000 oil and gas wells to differentiate the shallow and deep groundwater sources in eight California counties.

The researchers stated that this is good news for California. On the other hand, there are some complications to consider. This includes more expenses for pumping as the water is about 1,000 to 3,000 feet underground. Another thing is that some of the deep aquifer water is brinier, which has higher salt concentration. This requires desalination or other treatment so that it can be used for drinking or agriculture.

One more concern is that the oil and gas activities are occurring directly into as much as 30 percent of the sites where the deep groundwater resources are located. The researchers said that just because a company has hydraulically fractured or used some chemical treatment near an aquifer, this does not mean that the water is ruined. Kang explained that they need to use this water for a decade, so it's definitely worth protecting.